1. Field of the Invention
The present invention relates to an image interface device which is capable of processing multi-level image data (one pixel per n bits for example, eight bits) and binary image data (one pixel per one bit) through the same data bus when necessary image processings are conducted on the image input from a scanner and the resultant image is then outputted to a printer.
2. Description of the Related Art
In conventional digital copying machines, various types of image processings are conducted on the image data output from a scanner for photoelectrically reading images using a CCD or the like, and the resultant image data is supplied to a printer, such as an ink jet printer, for printing.
In such digital copying machines, the scanner reads images in the form of multilevel data of n bits per pixel and thereby reads halftones of an original, and outputs the multilevel image data read to a subsequent processing unit. When a printer of the type in which images are reproduced by the presence and absence of dots, for example, an ink jet, is used, the multilevel image data on which various image processings are conducted is converted into binary data of one bit per pixel and then supplied to the printer.
Thus, multilevel data is output from the scanner, and binary data is supplied to the printer.
It has also been proposed to connect an external unit, such as a computer system or a communication unit, to the digital copying machine and thereby use the digital copying machine as an input device for inputting image data to the external unit or as an output device for outputting image data from the external unit.
How the digital copying machine and the external unit are connected with each other is determined by the type of image data the external unit handles, i.e., depending on whether it is multilevel or binary.
Hence, the type of connectable external unit is limited if only either the binary or multilevel image data is handled by the interfacing device which provides interface between the external unit and the digital copying machine.
Furthermore, if interfaces for both the binary and multilevel image data are provided to handle both kinds of data, the configuration of the device becomes complicated. If only one type of data is handled in such a device, the function and configuration for the other type of data is wasted.